Fuel feed devices for internal combustion engines

ABSTRACT

The fuel feed device includes an injection valve actuated by an electromagnet which is energized over a variable fraction of each revolution of a rotating member driven by the engine. On acceleration with the opening of the main throttle member of two throttle members it is advantageous to increase the richness of the air/fuel mixture admitted to the engine to obtain freer and more regular acceleration. The source of fuel under pressure is constituted by a fuel pump on the delivery pipe of which acts a pressure regulator which comprises a relief valve tending to open under the effect of the delivery pressure of the pump and to close under the effect of the suction existing in the section of the intake pipe comprised between its two throttle members. The suction is transmitted by a linking channel to a diaphragm to which the relief valve is coupled. The variable volume chamber is connected to the linking channel between a calibrated orifice and the diaphragm of the pressure regulator and is controlled by means adapted to increase its volume on opening of the main throttle member.

United States Patent Mennesson ]March 20, 1973 [5 FUEL FEED DEVICES FOR INTERNAL Primary Examiner-Laurence M. Goodridge COMBUSTION ENGINES Assistant Examiner-Cort Flint [75] Inventor: Francois Mennesson, Namcrrc Attorney-Stevens, Davis, Miller & Mosher France 57 ABSTRACT [73] Asslgnee' gl f z fgfg gz g jg The fuel feed device includes injectionyalve actu- France ated by an electromagnet which IS energized over a variable fraction of each revolution of a rotating Filed; 1971 member driven by'the engine. On acceleration with [21] APPL NOJ 189,532 the opening of the main throttle member of two throttle members it is advantageous to increase the richness i of the air/fuel mixture admitted to the engine to ob- [301 Apphcatmn Pmmty tain freer and more regular acceleration. The source 0m. 30, 1970 France ..39332 of fuel under Pressure is constituted y a fuel P p the delivery pipe of which acts a pressure regulator [52] US. Cl ..123/32 EA, 123/119 R, 123/32 AE which comprises a relief valve tending to open under [51] Int. Cl. ..F02b 3/10, F02m 51/02 the effect of the delivery pressure of the pump and to [58] Field of Search ..123/32 EA, 32 AB, 119 close under the effect of the suction existing in the section of the intake pipe comprised between its two [56] References Cited throttle members. The suction is transmitted by a linking channel to a diaphragm to which the relief valve is UNITED STATES PATENTS coupled. The variable volume chamber is connected 3,596,645 8/1971 Mennesson 123/32 AE to the linking channel between a calibrated orifice and 3,662,721 5/1972 Klein ..123/32 AE the diaphragm of the pressure regulator and is con- K0118 B means to increase its volumc on opening of the main throttle member.

2 Claims, 2 Drawing Figures PATENTEDHARZO 191s SHEET 10F 2 FUEL FEED DEVICES FOR INTERNAL COMBUSTION ENGINES The invention relates to fuel feed devices, for inter: nal combustion engines, of the type which comprise, on one hand, in their intake pipe, upstream of a main throttle member actuated by the driver, an auxiliary throttle member which opens automatically and progressively in proportion as the flow of air in the said pipe increases, on the other hand, means for injecting liquid fuel under pressure into the portion of this pipe situated downstream of the main throttle member, and,

on the other hand lastly, a metering system sensitive to the position of the auxiliary throttle member and adapted to adjust the flow rate of injected fuel in such a way that the richness of the air/fuel mixture passing in the intake pipe is substantially constant, at least for certain conditions of operation of the engine, the said injection means being constituted by a source of fuel under pressure of which the delivery circuit, opening into the abovesaid portion of the intake pipe, is controlled by at least one injection valve actuated by an electromagnet.

The invention relates more particularly to those devices of the type concerned which have been described in US. Pat. No. 3,543,739, and of which the abovesaid metering system comprises a member driven in continuous rotary movement and capable, by acting on the energization of the electromagnet, of determining over a fraction only of each of its revolutions the opening of the injection valve, this system being arranged so that it increases the said fraction in proportion as the opening of the auxiliary throttle member increases and vice versa.

The invention relates more particularly also to those devices of the type concerned of which the source of fuel under pressure is constituted by a fuel pump on the delivery pipe of which there acts a pressure regulator which comprises a relief valve tending to open under the action of the delivery pressure of the pump and to close under the effect of the suction existing in the section of the intake pipe comprised between its two throttle members, which suction is transmitted through a linking passage to a diaphragm to which the relief valve is coupled.

Of course, on acceleration, that is to say on opening of the main throttle member, it is advantageous to increase the richness of the air/fuel mixture admitted into the engine to obtain freer acceleration without irregularities.

The concept of the pressure regulator, which establishes the fuel pressure as a function of the suction which exists in the intake pipe downstream of the auxiliary throttle member, enables, in practice, the preservation of the correct richness of the mixture, on acceleration.

Now, the needs of depollution of exhaust gases, which impose operation at a stabilized rate with extremely poor mixtures, obliges particularly the enrichment of the mixture during periods of acceleration. It is hence necessary to utilize a supplementary device to obtain such a result.

To this end, the device of the type defined above is characterized by the fact that a variable volume chamber is connected to the abovesaid linking passage between a calibrated orifice and the diaphragm of the regulator and is controlled by means adapted to increase its volume on opening of the main throttle member.

The increase in volume of the chamber which has just been defined causes an increase in the suction acting on the diaphragm of the regulator and, consequently, an increase in the pressure of the fuel directed towards the injection valve, that is to say, finally, an increase in the flow rate of the fuel, all other things being equal.

It should be noted that the increase in the suction acting on the diaphragm and, consequently, the increase in the flow rate of the fuel are all the greater as the opening of the main throttle member is more rapid.

The invention will, in any case, be well understood by means of the supplementary description which follows, as well as of the accompanying drawings, which supplementary description and drawings relate to a preferred embodiment, given purely by way of illustrative but non-limiting example.

In the drawings:

FIG. 1 shows in diagrammatic elevation with portions cut out, one embodiment of a fuel feed device constructed according to the invention; and

FIG. 2 shows a cross-section along the line -11 of the embodiment of FIG. I.

In order to construct a fuel feed device for vehicle engines or the like, general practice is as follows.

As regards the device as a whole, it is constituted in any suitable manner so that it comprises:

on one hand, in its intake pipe 1, upstream of a main throttle member 2 actuated by the driver, an auxiliary throttle member 3 which opens automatically and progressively in proportion as the flow rate of air in the pipe 1 increases, the direction of flow being indicated by the arrow F in FIG. 1;

on the other hand, means for injecting under pressure liquid fuel into the portion of the pipe 1 situated downstream of the main throttle member 2;

on the other hand, lastly, a metering system sensitive to the position of the auxiliary throttle member 3 and adapted to adjust in such a way the flow rate of fuel injected that the richness of the air/fuel mixture passing in the pipe 1 is substantially constant, at least for certain conditions of operation of the engine.

According to the invention, in the embodiment shown, the auxiliary throttle member 3 is constituted by a butterfly valve keyed on an axle 4. This valve is actuated by a pneumatic device comprising a diaphragm 5 separating from one another two chambers 6 and 7. The chamber 6 is connected by a passage 8 to a chamber 9 constituted by the section of the pipe 1 which is comprised between the main throttle member 2 and the valve 3. The axle 4 is rigidly fixed to a lever 10 provided, at its free end, with a pin 11 which cooperates with the end of a rod 12, which is connected to the diaphragm 5. A spring 13 tends constantly to close the valve 3 against the action of the suction trans mitted into the chamber 6. The chamber 7 is placed at atmospheric pressure by a channel 14 starting preferably from the air intake 15 of the pipe 1.

Of course the angular position taken up at each moment inside the pipe 1 by the valve 3 corresponds to the air flow rate which is passing in this pipe. The greater the air flow rate, the more the valve 3 opens, a substantially constant suction (or varying according to the characteristics of the spring 13) being established in the chamber 9 comprised between the two throttle members 2 and 3. The valve 3 could be replaced by equivalent throttle members, of which examples have been described in the US. Pat. No. 3,543,739.

The abovesaid injection means are constituted by a source of fuel under pressure which will be described in more detail below and of which the delivery circuit, opening into the pipe 1 downstream of the main throttle member 2, is controlled by at least one injection valve 16 actuated by electromagnet 17.

The metering system is made to include a flat and opaque disc 18 which is borne by a shaft 19, connected preferably to the internal combustion engine (not 'shown) supplied by the device, so that the disc is driven in a continuous rotary movement around an axis perpendicular to its plane. The disc 18 is interposed between a light source 20 and a receiver such as a photodiode or photoelectric cell 21,, borne by a common support 22 connected to the auxiliary throttle member 3 and it is pierced by at least one window 23 adapted to allow the beam coming from the source 20 to arrive at the cell 21. The cell 21 is arranged to control the energization of the electromagnet 17 according as it is illuminated or not and the assembly is such that the electromagnet is energized over a fraction of each of the revolutions of the disc 18 which varies in the same sense as the degree of opening of the throttle member 3.

The light source 20 may be constituted by a lamp which is adapted to be supplied by a battery 24 as soon as the ignition contact 25 of the engine isclosed and which is arranged in a hollow boss 26 pierced by a hole. This hole is oriented so as to direct a light beam on to the cell 21, through a hole passing through a hollow boss 27 where the said cell is housed.

In the embodiment shown, the bosses 26 and 27 are borne by the ends of the U support 22 which straddles the disc 18 so that the source 20 and the cell 21 occur on each side of the disc and which is rigidly attached to the axle 4, the latter being parallel to the shaft 19 as well as to the light beam received by the cell 21.

To utilize the currents generated in the cell 21, there can be interposed between the latter and the electromagnet 17 an amplifying relay 28.

When the internal combustion engine possess several cylinders each supplied by a valve 16 actuated by an individual electromagnet 17, all the electromagnets can be made to be controlled simultaneously or there can be provided a distributor 30 synchronized with a disc 18 to send successively intermittent energizing currents into the various electromagnets, the disc possessing as many windows 23 as there are cylinders to be supplied. These windows are distributed regularly around the shaft 19 and have each a shape such that the fraction of a revolution during which it enables the cell 21 to be eliminated normally increases in proportion as the throttle member 3 opens, that is to say (in the embodiment shown) in proportion as the bosses 26, 27 approach the shaft 19.

Of course the fuel feed device which has been described operates as follows.

In proportion as the air flow rate in the pipe 1 increases, the throttle member 3 opens by driving the support 22 in the sense which causes the bosses 26 and 27 to approach the shaft 19. Each of the positions of these bosses corresponds to a different radius of the disc 18. 7

Since the shape of each window 23 has been determined so that the fraction of a revolution, during which it allows the light ray coming from the source 20 to pass towards the cell 21 (creation of a current in conductor 31), increases in proportion as the latter elements approach the shaft 19, it is ensured that the flow rate of the fuel delivered by each injection valve 16 varies in the same sense as the air flow rate in the pipe 1.

This being the case, the source of liquid under pressure is constituted by a fuel pump of which the aspiration pipe 51 dips into a fuel reservoir 52 and on the delivery pipe 53 of which a pressure regulator 54 acts. The latter comprises a relief valve 55 tending to open under the effect of the delivery pressure of the pump and to close under the effect of the suction existing in the chamber 9, which suction is transmitted through a linking channel 56 on to a diaphragm 57 to which the valve 55 is coupled by a rod 58. The valve 55 cooperates with a seat 59 which constitutes the outlet of a chamber 60 connected by a branch channel 61 to the delivery pipe 53. The linking channel 56 ends at a variable volume chamber 62 bounded by one surface of the diaphragm 57, the other surface being placed at atmospheric pressure, for example by an orifice 63. The assembly is such that the valve 55 opens as soon as the pressure in the pipe 53 exceeds a value determined by the surface of the diaphragm 57 and by the suction exerted on the latter.

According to the invention, a variable volume chamber 84 is connected to the linking channel 56, between a calibrated orifice 85 and the chamber 62 bounded by the diaphragm 57 of the regulator 54, and is controlled by means adapted to increase its volume on the opening of the main throttle member 2.

In the embodiment shown, the variable volume chamber 84 is bounded inside a fixed cylinder 86, by a piston 87 mechanically connected to the main throttle member 2. The latter being constituted by a butterfly valve keyed on a rotary axle 88, the piston 87 is connected to it by a lever 89 rigidly fixed to the axle 88 and by a rod coupled by its two ends respectively to the piston 87 and to the free end of the lever 89.

The assembly of the lever 89 and of the rod 90 is arranged so that opening of the main throttle member 2 causes movement of the piston 87 in the sense which increases the volume of the chamber 84.

The portion of the cylinder 86, which is situated on the other side of the chamber 84 with respect to the piston 87, is placed at atmospheric pressure.

The operation of the supplementary means according to the present improvements is as follows.

On opening of the main throttle member 2, the volume of the chamber 84 is increased, which, by reason of the presence of the calibrated orifice 85, increases the suction which acts on the diaphragm 87 of the regulator 54. Increase in the suction is all the greater as the orifice 85 is smaller and as the opening of the main throttle member 2 is more rapid. There is thus indeed obtained, on acceleration, an increase in the pressure of the fuel upstream of the injection valve 16 and, consequently, an increase in the flow rate through this valve for a same duration of opening of the latter and, lastly, an increase in the richness of the air/fuel mixture delivered to the engine. The increase in the richness thus obtained is all the greater as the opening of the throttle member 2 is more rapid.

As soon as the throttle member 2 has stopped after its opening movement, the value of the suction acting on the diaphragm 57 is gradually restored to that of the suction existing in the chamber 9 and the operation becomes then the same as in the absence of the means 86 to 90, according to the present improvements.

As is self-evident, and as emerges already from the foregoing, the invention is in no way limited to those of its methods of application, nor to those of its methods of production of its various parts, which have been more especially indicated; it encompasses, on the contrary, all variations, especially that where the piston 87, which limits the variable volume chamber 84, is replaced by an equivalent movable or deformable element.

lclaim:

1. Fuel feed device, for an internal combustion engine, which comprises, in its intake pipe, upstream of a main throttle member actuated by the driver, an auxiliary throttle member which opens automatically and progressively in proportion as the air flow increases in the said pipe, means for injecting liquid fuel under pressure into the portion of said pipe situated downstream of the main throttle member, and a metering system sensitive to the position of the auxiliary throttle member and adapted to adjust the flow of fuel injected in such a way that the richness of the air/fuel mixture passing into the intake pipe is substantially constant, at

least for certain operational conditions of the engine, said injection means being constituted by a source of fuel under pressure whose delivery circuit, opening into said portion of the intake pipe, is controlled by at least one injection valve actuated by an electromagnet, the metering system comprising a member driven in a continuous rotary movement and capable, by acting on the energization of the electromagnet, of determining over a fraction only of each of its revolutions the opening of the injection valve, said metering system being arranged so that it increases and decreases said fraction in proportion as the opening of the auxiliary throttle member increases and decreases respectively, said source of fuel under pressure being constituted by a fuel pump in the delivery pipe of which acts a pressure regulator which comprises a relief valve tending to open under the effect of the delivery pressure of the pump and to close under the effect of the suction existing in the section of the intake pipe comprised between said main and auxiliary throttle members, which suction is transmitted through a linking passage to a diaphragm to which the relief valve is coupled, a variable volume chamber being connected to said linking passage between a calibrated orifice and the diaphragm of the regulator and controlled by means adapted to increase its volume on the opening of the main throttle member.

2. Fuel feed device according to claim 1, wherein the variable volume chamber is limited inside a fixed cylinder by a piston mechanically connected to the main throttle member. 

1. Fuel feed device, for an internal combustion engine, which comprises, in its intake pipe, upstream of a main throtTle member actuated by the driver, an auxiliary throttle member which opens automatically and progressively in proportion as the air flow increases in the said pipe, means for injecting liquid fuel under pressure into the portion of said pipe situated downstream of the main throttle member, and a metering system sensitive to the position of the auxiliary throttle member and adapted to adjust the flow of fuel injected in such a way that the richness of the air/fuel mixture passing into the intake pipe is substantially constant, at least for certain operational conditions of the engine, said injection means being constituted by a source of fuel under pressure whose delivery circuit, opening into said portion of the intake pipe, is controlled by at least one injection valve actuated by an electromagnet, the metering system comprising a member driven in a continuous rotary movement and capable, by acting on the energization of the electromagnet, of determining over a fraction only of each of its revolutions the opening of the injection valve, said metering system being arranged so that it increases and decreases said fraction in proportion as the opening of the auxiliary throttle member increases and decreases respectively, said source of fuel under pressure being constituted by a fuel pump in the delivery pipe of which acts a pressure regulator which comprises a relief valve tending to open under the effect of the delivery pressure of the pump and to close under the effect of the suction existing in the section of the intake pipe comprised between said main and auxiliary throttle members, which suction is transmitted through a linking passage to a diaphragm to which the relief valve is coupled, a variable volume chamber being connected to said linking passage between a calibrated orifice and the diaphragm of the regulator and controlled by means adapted to increase its volume on the opening of the main throttle member.
 2. Fuel feed device according to claim 1, wherein the variable volume chamber is limited inside a fixed cylinder by a piston mechanically connected to the main throttle member. 